c#中使用多线程（图）[1]

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

using System.Threading;

namespace student
{
 /// <summary>
 /// Form1 的摘要说明。
 /// </summary>
 public class Form1 : System.Windows.Forms.Form
 {
  private System.Windows.Forms.Button button1;
  private System.Windows.Forms.Button button2;
  private System.Windows.Forms.Button button3;

  ArrayList threads = new ArrayList();

  private System.Windows.Forms.ListView listView1;
  private System.Windows.Forms.ColumnHeader columnHeader1;
  private System.Windows.Forms.ColumnHeader columnHeader2;
  /// <summary>
  /// 必需的设计器变量。
  /// </summary>
  private System.ComponentModel.Container components = null;

  public Form1()
  {
   //
   // Windows 窗体设计器支持所必需的
   //
   InitializeComponent();

   //
   // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
   //
  }

  /// <summary>
  /// 清理所有正在使用的资源。
  /// </summary>
  protected override void Dispose( bool disposing )
  {
   if( disposing )
   {
    if (components != null)
    {
     components.Dispose();
    }
   }
   base.Dispose( disposing );
  }

  #region Windows 窗体设计器生成的代码
  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void InitializeComponent()
  {
   this.button1 = new System.Windows.Forms.Button();
   this.button2 = new System.Windows.Forms.Button();
   this.button3 = new System.Windows.Forms.Button();
   this.listView1 = new System.Windows.Forms.ListView();
   this.columnHeader1 = new System.Windows.Forms.ColumnHeader();
   this.columnHeader2 = new System.Windows.Forms.ColumnHeader();
   this.SuspendLayout();
   //
   // button1
   //
   this.button1.Location = new System.Drawing.Point(24, 216);
   this.button1.Name = "button1";
   this.button1.TabIndex = 1;
   this.button1.Text = "Add";
   this.button1.Click += new System.EventHandler(this.button1_Click);
   //
   // button2
   //
   this.button2.Location = new System.Drawing.Point(104, 216);
   this.button2.Name = "button2";
   this.button2.TabIndex = 2;
   this.button2.Text = "Del";
   this.button2.Click += new System.EventHandler(this.button2_Click);
   //
   // button3
   //
   this.button3.Location = new System.Drawing.Point(184, 216);
   this.button3.Name = "button3";
   this.button3.TabIndex = 3;
   this.button3.Text = "DelAll";
   this.button3.Click += new System.EventHandler(this.button3_Click);
   //
   // listView1
   //
   this.listView1.Columns.AddRange(new System.Windows.Forms.ColumnHeader[] {
                      this.columnHeader1,
                      this.columnHeader2});
   this.listView1.FullRowSelect = true;
   this.listView1.GridLines = true;
   this.listView1.Location = new System.Drawing.Point(0, 0);
   this.listView1.Name = "listView1";
   this.listView1.Size = new System.Drawing.Size(288, 208);
   this.listView1.TabIndex = 5;
   this.listView1.View = System.Windows.Forms.View.Details;
   //
   // columnHeader1
   //
   this.columnHeader1.Text